US and UK share a more than 'special relationship'

Mr Cameron and Mr Obama said the relationship between the US and UK is based on shared values

The White House is well aware how sensitive some British people are about "the special relationship" and how every hiccough is fretfully interpreted as a slight.

So part of the purpose of President Barack Obama's visit to the UK is to nail the perception that he doesn't care.

It is also to get the UK and Europe to do more of what used to be seen, by some at least, as the US's role in the world.

In their joint article in The Times newspaper, Prime Minister David Cameron and Mr Obama redefine what was once merely special as "essential".

They argue that it is not just founded on a deep emotional commitment but also on shared values. They say it is strong because it works.

They say they see eye to eye and will build on the relationship in a wide range of areas from economy to countering terrorism.

Middle East action

Both men throw their weight behind the Arab spring, justifying action in Libya and saying they will not stand by and see people's aspirations crushed in a hail of bombs, bullets or mortar fire.

It is a solid attempt to put to rest the argument that the Pacific president really doesn't care much for Britain.

It's true he didn't much like Gordon Brown and did have different foreign policy priorities, but he has tried to bury that perception in an avalanche of love.

What this article doesn't answer is the limit to liberal interventionism.

On the surface, it sounds like an Anglo-American pact to put right the wrongs of the world, by any force necessary.

It is unclear how these new pals behave differently from the old pals, George W Bush and Tony Blair.

There is no timetable, however, for the invasion of Syria or indeed Saudi Arabia.

There is no suggestion where the money is coming from when the two countries are planning to do less because they are strapped for cash.

There is no suggestion of how they will persuade other, less assertive countries to join them.

Indeed, this manifesto of the essential relationship may serve to carry them through the next couple of days and be a convenient explanation of some disparate actions, rather than be a real blueprint for action into their second terms.